Steam and air feeding apparatus for boiler-furnaces.



No. 703,732. Patented'july I, I902.

A a]. MARSHALL. j STEAM AND AIR FEEDING APPARATUS FOR BOILER FURNACES;

(Application filed. Dec. 21, 1901.)

(No Model.) I 2 Sheets-Sheet 1.

Patented July I, 1902.

J. MARSHALL. STEAM AND AIR FEEDING APPARATUS FOR BOILER FURNACES.v

(Application filed Dec. 21, 1901.)

2 Sheets-Sheet 2.

(No Model.)

' i'og. 5.

UNITED STATES PATENT OFFICE.

JAMES MARSHALL, .OFLDUNFERMLINE, SCOTLAND.

ST EAMAND AIR FEEDING APPARATUS FOR'BOILER-FURNACES.

SPECIFICATION forming part of new r; Patent No. dated'J 1, 1902- Application filed December 21, 1901. Serial No. 86,813. (No model.)

To ctZZ whom it may concern.-

Be it known that LJAMES MARsHALL,a subject of the King of the United Kingdom of Great Britain and Ireland, and a resident of Oakbank,Rose street,Dunfermline,Scotland, have invented Improvements in or Relating to Steam and Air Feeding Apparatus for Boiler- Furnaces, of which the following is a specification. J

This invention relates'to improvements in or relating to steam-boiler furnaces for the purpose of consuming smoke and saving fuel.

Figure 1 is a side view. of a steam-boiler with the boiler-plate A broken to show the furnace with my improvements applied thereto. Fig. 2 is asection, on an enlarged scale, on the line 1 2, Fig. 1. Fig. 3 is an enlarged detail.

Along the one side of the furnace chamber or tube B, at a level above the fire-bars O, is an air tube or chamber D, which extends from the front of the furnace back to and over the bridge E. Passing through the center of the said air-pipe is a steam-pipe f with perforations f therethrough. The air-charmber D,surrounding the said steam-pipe,is provided with corresponding apertures 01, (shown in Fig. 2,) the arrangement being such that as the steam issues through the perforations f of the steam-pipe (see arrow Fig. 2) and through the corresponding apertures d of the air-pipe D it draws the highly-heated air along with it, so that the two commingling strike across the furnace, and bywhich agency the smoke from the fire-grate is caused to be consumed, the eflect of the combined blast of highly-heated air and steam being similar to a Bunsen blower.

In order to protect the air tube or chamber D from the efiects of the heat, itis containedwithin an outer water-tube H, the passagefor the combined highly-heated air and steam through the said water-tube being effected by means of the ferrule. or water-tight connection shown at d, Fig. 2.

The steam is supplied from the crown of the boiler at G. It then passes-alongside the water-jacket tube H, as shown more particularly in Fig. 2, until it enters the closed end of the air-tube D at the back end of the furnace.

(See Fig. 1.) After leaving the said air-tube at the front end of the furnace the superheated steam passes down the pipe F and then up the depending open-ended air-tube d, the blast of steam into and up the said tube atzd' inducing a current of air up the said tube and into and along the air-tube in the furnace. The connection of the said airinlet tube 01 with the air-tube D, which passes through the furnace, is shown in the enlarged detail view, Fig. 3, and consists in the employment of the cast-iron sleeve J, into which the air-inlet mouthpiece d is fixed and to which the hot-air tube D and water-tube H are fixed, the said sleeves J being bolted to the front plate I) of the furnace.

The supply of water for the water-jacket tube H is obtained from the pipes h h, the

one above the fire-bars at the front end of the furnace and the other below the level of the fire-bars at the back end of the furnace, as shown in Fig. 1, the said pipes being connected to the water of the boiler at 71. h as shown in the enlarged view Fig. 2, the ar- -rangement being such that there is efiected a continuous and rapid circulation of water through the water-jacket tube. The said circulation through the highly-heated waterjacket tube also increases the efficiency of the boiler by adding to the water-heating surface or area. K in this figure shows the position of the fire-door as seen from the back end of the furnace. '1

In accordance with myimprovements by virtue of the air-tube and steam-pipe being mounted above the-furnace-bars and extending from end to end of the furnace they become very highly heated, and thus supply the combined air and steam of the furnace at a very high temperature, particularly with -.reference to the steam-pipe F, which causes the steam to be very highly heated on its way from the front of the furnace to behind the bridge, where it enters the air-tubeDl By virtue of these arrangements oomple'te'combustion of the fuel is effected. Because of the mechanical stirring action of the steam and air a rapid commotion is created in the fire-box, swirling the flame round the flue and causing it to impinge on the heating-surfaces, and thereby increasing the efficiency of the boiler and at the same time cutting up and consuming the smoke.

I claim- 1. The combination of the fire-chamber B; grate C 0; bridge E; air-tube D having a projecting inlet-mouthpiece (1 near one end and extending from front to rear on the interior of the fire-chamber; steam-pipefwithin the tube D having a number of jet-apertures f steam-pipe F connected with the steamspace of the boiler at G and communicating with one end of the pipe f to convey steam under pressure thereto; pipe F connected with the outlet end of the pipe f and discharging steam therefrom into the mouthpiece d of the tube D; Water-tube H surrounding the air-tube D; thimbles cZ fixed in the adjacent walls of the concentric tubes D and II opposite the steam-jet openings f and delivering jets of combined steam and air within the fire-chamber; and pipes h h forming communication with the respective ends of the water-tube H and the water-space of the boiler, substantially as and for the purposes described.

2. The combination of the concentric tubes D and H for air and water respectively; the flanged cast-metal sleeve J in which the united front ends of the said tubes are mounted; the steam-pipe f, Within the air-tube D; the mouthpiece d communicating at its inner end with the tube D and open at its outer end to admit air thereto; and outlet-pipe F from steam-pipe f, terminating in a jet-nozzle Within the mouthpiece (1 so as to inject air therethrongh, substantially as described.

JAMES MARSHALL.

Witnesses:

JOHN D. KEILLER, ALEX. C. DOBBIE. 

